If these predictions come to pass, their fulfillment will have lasting effects upon America in the 2020s and beyond. In 2008, as the Obama administration prepared to take control in Washington, retired Army Gen. Barry McCaffrey offered a list of bold predictions for the coming five years. Some of them bore out: The economy performed well globally despite the Great Recession, relations with Russia became more hostile without devolving into outright dysfunction, and the United States withdrew from Iraq right at the 36-month mark, which McCaffrey specified. Other predictions, such as a North Korean collapse, improved prospects for success in...